# CVE-2023-2731: Null dereference in libtiff

> A local attacker can cause a denial of service by crafting a TIFF file that triggers a NULL pointer dereference in Libtiff's LZW decoder.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 17 May 2023
- **Updated:** 22 Jan 2025
- **Also known as:** AZL-26756, AZL-43795, AZL-45003, BELL-CVE-2023-2731, DEBIAN-CVE-2023-2731, GHSA-g995-h8wx-7qw6, JLSEC-2025-303, OESA-2023-1316

## What is CVE-2023-2731?

CVE-2023-2731 is a medium-severity vulnerability in Fedoraproject Fedora, published on 17 May 2023. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

A NULL pointer dereference flaw was found in Libtiff's LZWDecode() function in the libtiff/tif_lzw.c file. This flaw allows a local attacker to craft specific input data that can cause the program to dereference a NULL pointer when decompressing a TIFF format file, resulting in a program crash or denial of service.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2023-2731?

It affects 3 products.


Products: Fedoraproject Fedora, Libtiff Libtiff, Redhat Enterprise Linux.

## How do I fix CVE-2023-2731?

Apply the vendor's patch.

## Is CVE-2023-2731 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-2731 exists.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-2731 and fix it if it is affected.

What it is: CVE-2023-2731 is a medium-severity vulnerability in Fedoraproject Fedora, published on 17 May 2023. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-2731 exists.

Affected product: Fedoraproject Fedora. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-2731/ (Markdown: https://insights.sbomify.com/CVE-2023-2731/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-2731
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-2731
- OSV: https://osv.dev/vulnerability/CVE-2023-2731

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-2731/
Summaries are generated and may contain mistakes; the official description above is the record.